Re: [ros-users] reverse kinematics using robot_state_publish…

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Author: Sachin Chitta
Date:  
To: ros-users
Subject: Re: [ros-users] reverse kinematics using robot_state_publisher ?
Hi Ugo,

You can use KDL to do inverse kinematics using one of the inverse kinematics
solvers in the package. These are numerical solvers that operate on a KDL
chain. First use the kdl_parser package to create a KDL chain and then
initialize an inverse kinematics solver for the chain. The solution tends to
be dependent on the initial state you pass into the solver and can sometimes
get stuck in local minima. Also, I am not sure about how well the solvers
handle joint limits. I believe more advanced solvers are in the works but I
will let the orocos folks comment on that.

Have a look at the api page here
http://orocos.org/kdl/UserManual/kinematic_solvers for more examples.

The other option is to write your own solver (we have one for the PR2 that
takes in a hint for one of the joint angles and then computes the other 6
analytically - www.ros.org/wiki/pr2_arm_kinematics)

Sachin

On Wed, Apr 7, 2010 at 3:28 AM, Ugo Cupcic <> wrote:

> Hi all,
>
> Is it possible to use robot_state_publisher or some other ROS stack to
> do reverse kinematic on my urdf model?
> Or do I need to implement my own using the "Coding a realtime Cartesian
> controller with KDL" tutorial ?
>
> Cheers,
>
> Ugo
>
>
> --
> Ugo Cupcic         |  Shadow Robot Company | 
> Software Engineer      251 Liverpool Road
> need a Hand?           London  N1 1LX       | +44 20 7700 2487
> http://www.shadowrobot.com/hand/              @shadowrobot

>
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>




--
Sachin Chitta
Research Scientist
Willow Garage